| Conflict: | Siege of Ryūgasaki |
| Partof: | the Sengoku period |
| Date: | 1545 |
| Place: | Ryūgasaki, Shinano Province, near Lake Suwa |
| Result: | Takeda victory |
| Combatant1: | Forces loyal to Tozawa Yorichika |
| Combatant2: | Takeda family forces |
| Commander1: | Yoshinaga Mitoyoshi† |
| Commander2: | Takeda Shingen |
| Strength1: | 2,500 |
| Strength2: | 3,200 |
| Casualties1: | Unknown |
| Casualties2: | Unknown |
The 1545 siege of Ryūgasaki was one of many battles fought by Takeda Shingen in his bid to control Shinano Province during Japan's Sengoku period. The fortress was a satellite castle of Fukuyo, and was held by Tozawa retainer Yoshinaga Mitoyoshi. Yoshinaga himself was killed in battle while the fortress fell.